Screw driver



Dec. 8, i942. T. A. OLEARY 2,304,703

SCREW DRIVER Filed sept. 27, 1939.

INVENTOR.

In@ ATTORNEY.-

Patented Dec. 8, 1942 SCREW DRIVER Theodor A. OLeary, New York, N Y., assigner of forty-eight and one-third per cent to Winslow Foster, New York, N. Y.

Application september 27, 1939, serial No. 296,855

6 Claims.

This invention relates to new and useful improvements in screw drivers, and relates more particularly to an improved driver for driving a screw having a special type of slot formed in the head portion thereof.

The screw which is adapted to be driven by the driver constituting the present invention is disclosed in my copending application Serial No. 75,611, issued as Patent No. 2,182,092, such screw having a transverse slot inthe head, the lower wall of the slot being concavely curved and terminating just short of the peripheral edges of such head portion. The opposed side walls of the slot are not parallel as in a conventio-nal screw, but are upwardly and .inwardly convergf face of the head of the screw is in firm engageing in the central portion only, the terminal porf tions of such opposed side walls being substantially parallel to each other. Thus a transverse section taken through the center of the slot would present a dove-tail effect and a relatively conventional driver for driving such a screw would include a bit portion having a curved terminal or bit portion, the opposed side walls of such bit Apo-rtion being outwardly flanged to correspond generally with the side walls of the dovetailed slot.

To employ a. screw driver of this character in driving a screw of the aforementioned type, it is necessary to cause the bit to enter the slot from one end thereof, thus moving either screw or driver through a partial arc. It will thus be apparent that once the bit portions is in position in the screw slot, longitudinal displacement of the bit relative to the slot is impossible, and after the screw has been driven, the bit portion of the driver is removed from the slot in the same manner as it entered such slot.

It is one of the principal objects of the present invention to provide an improved driver for use in driving a screw of the aforesaid type, such driver having split bit portions which are longitudinally movable in a hollow shank. The lower end of the shank is rformed with a wall having an aperture substantially rectangular in sha-pe and of such size as to receive and support the two bit portions. When it is desired to drive a screw, these bit portions are moved outwardly from the lower end of vsuch shank and means are provided for causing such bit portions to sepa- -rate sufficiently to engage the `screw lot at opposite ends thereof. Once in this position, the bit portions are again drawn into the shank, closing as theyl move inwardly, and when they have come to rest in their fully retracted position, the adjacent walls of such split bit portions are in meeting engagement and the upper surment with the lower surface of the shank. Thus, during the driving operation the screw is maintained in rigid, axial alignment with the shank of the driver and both transverse and longitudinal movement of the screw relative to the driver is prevented.

This greatly aids in the rapid driving of the screw, and when the screw has been driven ullt7 home, novel means are provided for permitting rapid release of the flanged bit portions from the screw. It is accordingly another object of the invention to provide an improved driver of this general character having a pair of split bit portions rmly supported in the lower end of a shank or other supporting means, such shank further being provided with means for controlling the operation of the split bit portions at a po-int remote therefrom. 4

The principal embodiment of the invention illust-rated in the drawing is a driver of the foregoing character adapted to be received in a chuck of a power driver, although it is quite apparent that a conventional handle could be placed upon the upper end of the shank and the driver used manually.

In the drawing:

Fig. 1 is a broken side elevation, partially in section, of the preferred embodiment of the present invention;

Fig. 2 is a view similar to Fig. l, but is taken at right angles to the View shown in Fig. l;

Fig. 3 is an elevation oi the lower end of the driver;

Fig. 4 is a broken longitudinal section taken on line 4 4 of Fig. 2;

Fig. 5 is a transverse section taken on line 5-5 of Fig. 4;

Fig. 6 is a View showing the two bit portions in closed or opera-tive position and the controlling mechanism of such bits, the view also showing a portion of the screw in section;

Fig. 'l is a broken, enlarged, longitudinal section of a portion of the device;

Fig. 8 is an exploded view of the bit portions and the controlling means therefor;

Fig. 9 is a top plan view of a. screw head having a pair of the special slots formed at right angles to each other;

Fig. l0 is a broken elevation of a driver showing the position of the split bit portions as they are about to enter the screw slot;

Fig. 11 is a broken longitudinal section showing a modied form of the present invention;

Fig. 12 is similar to Fig. 11, but is taken at right angles to the view shown in Fig. 1l.

The preferred embodimentl of the present invention is illustrated in Figs. l to 8, inclusive, and includes a shank structure I9 and split bit portions II and I2. The shank structure includes a barrel I4 and a solid shank portion I5 which is secured in the upper end of the sleeve by means of a set screw I6. The shank portion I5 illustrated in Fig. 1 is adapted to be received in the chuck of a power bit, although it will be appreciated that if a hand driver is desired, this shank portion may be more elongated and a han-A dle secured to the upper end thereof.

At the lower end of the barrel a pair of integrally formed, opposed extension portions I8 are provided, which portions receive a at, circular, bit supporting plate 20. This plate is formed with a rectangular opening 2| in which the bit portions II and I2 are positioned. The lower surface of the plate is further formed with a central, concave recess 22 to receive the upper surface of a screw in the case of a round or oval headed screw. This circular recess is, however, of lesser diameter than that of the conventional flat head 24 of a screw 3l of that character, as shown in Figs. 6 and 7, so that regardless of the shape of the upper surface of the head, the lower surface of the plate 25 is in meeting and firm engagement with such head during the driving operation.

The plate 20 is further formed with opposed, arcuate recesses 25 around the marginal edges thereof, such recesses being shaped complemental to the extensions I8 of the barrel and such extensions act to support the plate and to prevent rotative movement thereof relative to the barrel I4.

Thus it will be apparent that power applied to the shank structure I0, whether by machine or by manual means, is imparted to the plate 20 and to the side walls of the opening 2I therein, and thence to the bits. No other twisting power is applied to the bits.

Now to refer to the specific connection between the bits and the screw slot necessary to hold each other as they approach the terminals of the slots. formed with a tapered recess 36, also as shown in Fig. 7, and when the bits come togetherrin the manner hereinafter described, to the position shown in Fig. 6, these tapered portions 35 reside in such dove-tail slot in the screw.

It will accordingly be apparent that when the bits have been retracted into the barrel, the upper surface of the screw head will have been drawn into rm engagement with the lower surface of the plate 2i) and both longitudinal and transverse movement of the screw head relative to the bit portions is effectively prevented during the driving operation and such screw is held in relatively firm axial alignment with the shank structure I0. The plate 20 is further provided with integrally formed extensions 38, the external surface of such portions being such as to closely t the bore of the barrel I4. It will Thus, each bit portion Il and I2 is accordingly be seen that a recess 39 is formed in the center of such barrel through which the bit portions are free to travel. The extension portions 38 on the plate 20 are rmly secured within the bore in the barrel by means of a pin 4I passing through aligned apertures in the extension portions 38 and such sleeve, all as shown in Fig. 4.

The bit portion I2 is formed with an extension portion 44 and a pin 45 pivotally secures this portion to a longitudinally movable control rod 46 and when this rod is moved downwardly, by means hereinafter described, the bits move outwardly to their spaced, screw receiving positions. This bit portion is further formed with a slot 48 substantially in alignment with the shank when the bits are in driving position (Fig. 6). The slot is further formed with an upper extensionportion 49 lying at an angle of approximately 30 to the slot 48.

The bit portions II and I2 are of substantially the same thickness and lie in the same plane (Fig. 3), although the extension portion 44 of bit I2 lies above a similar, though shorter, extension portion 5I of bit II when viewed in position shown in Figs. 4 and 6. This portion 5I is formed with a slot 52 with extension portion 53.

When the bits have been retracted into the barrel, they are maintained in meeting engagement with each other by means of engagement of the external edges with the end walls 55 of slot 2l in plate 20 (Fig. 6) and in this position the pin 4I resides at the lower end of slots 48 and 52 in portions 44 and 5I. In this position, these slots are in alignment with each other.

Downward movement of rod 4S, and accordingly bit portion I2, causes similar movement of bit II by engagement between a curved shoulder 51 at the lower end of portion 44 and a complemental portion 58 of portion 5I. Similar complemental curved surfaces 57 and 58 are formed on the opposite sides of portions 44 and 5I respectively, to control movement of bit portion II during upward movement of bit I2.

It will be apparent that as bits I I and I2 move downwardly, their movements are parallel until the pin 4I gets to the ends of slots 48 and 52. Further movement of the bits causes the pin to engage slots 49 and 53 which are in effect cam faces. Thus the bits separate to receive the screw slot.

In the preferred embodiment of the present invention, control means for the rod 46 are provided whereby movement of the screw head against the extended bits causes the bits to spring back into operative position and at the end of the driving operation, longitudinal movement of the driver relative to the screw causes the bits to spring outwardly, thus freeing driver from screw. These means are as follows:

A longitudinally movable rod 60, which is preferably square or otherwise non-circular` in transverse section, is supported for longitudinal movement within the barrel I4 of the shank by means of a journal block 6I, which is secured within the sleeve by means of a screw or pin 62, such block having a central longitudinal aperture B3 therein. This rod is secured at its lowel` end to the rod 46 by means of a screw.65.v At its upper. end, the rod' 65 is preferably circular' in transverse section as shown at G'IV and at t'supper end a number of locking nuts 68 are positioned, the lower one engaging a washer 69. This washer abuts against the upper surface of, a second journalV block 'II whichr is longitudinally movable within the barrel I4. Movement of the block 'Il is controlled by means of a short sleeve13f carried on the exterior of the barrel |4, the external surface of such sleeve13 being knurled or otherwise 'rendered non-smooth, as shown at 14. A pin connects the sleeve 13 with the block 1|, such pin passing through an virregularly shaped aperture in the barrel I4, shown clearly in Fig. 2, and having elongated diagonal portions 11 and 18. A spring 19 is mounted concentrically of the circular portion 51 of the rod 60, the lower end of the spring passing through an aperture 88 in such square rod 69. The opposite end of this spring passes into a small aperture 8| in the block 1|.

The operation of this mechanism is as follows. The rod 60 is movable longitudinally but may not rotate because of square aperture 83 in the journal block 6|. Journal block 1| supporting the circular portion 51 of the rod 58 may rotate within the barrel |4, although such rotative movement is accomplished against the torsion of spring 19.

When a screw is to be driven and the bit portions are fully retracted (Fig. 4) the external knurled sleeve 13 is moved downwardly, thus moving rod 45 downwardly and also the bits and I2 in the same direction. This downward movement of sleeve 13 causes it to rotate as well for pin 15 must follow the opposed cam surfaces of slot 18 (Fig. 2). This rotative movement of sleeve 13 causes the spring 19 to become slightly wound. In the course of its downward movement, pin 15 passes point 84 marking the terminal of slot 13. The spring 19 performs the balance of the movement since in an elort to unwind, it causes pin 15 to ride down the cam surfaces of slot 11. sprung forward to screw slot engaging position, the bit portion also having moved apart to the position shown in Fig. 10.

The screw is now moved upwardly (manual actuation of sleeve 13 is unnecessary), pushing the bit portion back into sleeve I4. The only resistance afforded against this movement is that of spring 19 which is being wound while pin 15 rides up cam surfaces of slot 11.' When pin 15 passes point 84 the spring 19 does the rest and the screw is in driving position (Fig. 6). At the end of the driving operation, it is not necessary to manually operate sleeve 13 to release the screw. The driver is pulled away from the screw, the driver being maintained in axial alignment with the screwduring this operation. The pin 15 retraces its path and the bits move outwardly.

The foregoing and principal embodiment of the present invention is largely an automatic screw driver so far as actuation of the bits is concerned. The embodiment of the invention illustrated in Figs. 11 and 12 is substantiallythe same, except that manual non-automatic means for actuating the bits are provided. ln this instance, the barrel 86 is constructed substantially the same as the barrel |4 and the bit portions (not shown) are also the same as shown in the preferred embodiment of the invention. These bit portions are controlled by means of a longitudinally movable control rod 81, which is secured at the lower end thereof to the bits, as in the preferred embodiment, and at the upper end such rod passes through an aperture 88 in a journal block 89 positioned within the barrel 88 and is adapted to move longitudinally thereof.

At its upper end, the rod 81 is provided with a locking nut 89' which engages a washer 99', which in turn engages the upper end of the block 89. The control rod 81 is not keyed to the block 89.

The bit portions have now The upper end of the barrel 88 is provided with a 75 conventional screw driver handle 90. Manual movement of the rod 81 is provided by means of a sleeve 9| having a longitudinal bore 92 therein adapted to receive the exterior of the barrel 85. The external periphery 'of the sleeve 9| is knurled, as shown at 93. A diagonal slot 94 is vformed in the sleeve, such slot having a short terminal portion 95 at the upper end thereof, such portion lying at right Vangles to the barrel 85. A set screw 95 passes through the sleeve 9|, through the slot 94 and into the journal block 89. vA collar is keyed to control rod 81 and when journal block 89 is moveddownwardly the control rod likewise moves. When it is desired to move the bits outwardly, the sleeve 9| is turned in the direction ofthe arrow shown in Fig. 11, thus causing the screw 98 to ride on the cam surface afforded bythe slot 94, thus moving the' rod 81 downwardly. When'the screw is in place, the sleeve is turned in the opposite direction and the rod then moves upwardly, thus drawing the bit portions into the barrel. After the pin has left the diagonal portion 94 of the slot and enters the straight portion 95, it becomes in effect locked in such latter portion.

The screw illustrated in Fig. 9 is the same as that shown in Figs. 6 and '1 except that the head portion 91 thereof is provided withlslots 93 and 99 at right angles to each other. Y

It will be appreciated that the foregoing specic embodiments may be modified considerably without departing from the spirit of the invention as defined by the appended claims, Among the'more important aspects of the present invention is the provision 4of the split bits which are adapted to move longitudinally within the lower end of the shank of the driver, means being provided for spreading the bits apart as they move outwardly or downwardly and for causing the same to come together as they move upwardly or inwardly. The bit portions shown in the preferred embodiment of the invention are pivotally mounted on a common pivot member, although if desired, these bit portions could be made entirely separate from eachother, or on the other hand they could be provided with circular apertures rather than the elongated slots, and mounted togetherv on a common pivot, and means other than those illustrated employed for spreading the bits apart. It will also be apparent that other means for supporting the bits as they move outwardly may be employed and also means other than those shown may be employed for controlling such bits. For instance, instead of employing the longitudinally movable control rod 45, a rotating member might be employed. Or, in some instances, the bits might be controlled `at the lower-end of the driver only- It will further be apparent that the foregoing drivers may be used for driving screws other than those disclosed in my aforesaid co-pending application. The principal embodiment of such screw includes a slot having a concavely curved lower wall, the central portion of the side walls converging inwardly. The present driver however, may be used on a variety of screws having undercut slots in the heads thereof.

What I claim is:

1. A screw driver, adapted to drive a screw having a dovetail slot in the head thereof, comprising an elongated, hollow shank, a plate positioned at the forward end of the shank and having a substantially rectangular opening therein, a bit comprising a pair of undercut, complemental bit portions positioned within such open-- ing, said bit portions being formed withatsurfaces engaging the sides of said opening to prevent rotation therebetween, each bit portion having a longitudinal slot therein, a pin supported by the shank and passing through such slots in the bit portions, each slot having an inner extension lying at an angle to the slot whereby outward movement of the bit portions causes such portions to separate as the pin engages the slot extension portions, a longitudinally movable central rod connected with one bit portion and complemental shoulder portions formed on the several bit portions to cause them to move simultaneously.

2. A screw driver, adapted to drive a screw having a dovetail slot in the head thereof, comprising an elongated, hollow shank having a substantially rectangular opening in the forward end thereof, a bit comprising a pair of undercut, complemental bit portions positioned within such opening and having flat surfaces engaging the sides of said opening, each bit portion having a longitudinal slot therein, a pin supported by the shank and passing through such slots in the bit portion, each slot having an inner extension lying at an angle to the slot whereby outward movement of the bit portions causes such portions to separate as the pin engages the slot extension portions, manual means for causing inward and outward longitudinal movement of said bits comprising a central rod journalled within the shank for longitudinal, non-rotative movement, the shank having a substantially V-shaped slot therein, a member carried by the rod and formed with a portion lying in said slot and a spring restricting rotative movement of said member.

3. In a screw driver, adapted to drive a screw having a dovetail slot in the head thereof, the combination of a shank having a longitudinal bore therein and a substantially rectangular opening at the forward end of the shank, `a bit comprising a pair of undercut, complemental bit portions positioned within such opening, said bit portions being formed with fiat surfaces engaging the sides of said opening to prevent rotation therebetween, each bit portion having a longitudinal opening therein, a pin supported by the shank and passing through such openings in the bit portions, each opening having an inner extension lying at an angle to the opening, whereby outward movement of the bit portions causes such portions to separate as the pin engages the slot extension portions, and means comprising a longitudinally movable central rod for moving said bit portions outwardly.

4. In a screw driver, the combination of an elongated shank having a narrow opening in the forward end thereof and a longitudinal bore extending over the major portion of the jbalance of the shank, a bit comprising a pair of undercut, complemental bit portions positioned within such opening, said bit portions being formed with opposed, substantially flat surfaces engagingA the sides of said narrow opening to prevent rotation therebetween, each .bit portion having a longitudinal slot therein, a pin supported by the shank and passing through such slots in the bit portions, eaoh slot having an inner extension lying at an angle to the slot whereby outward movement of the bit portions causes such portions to separate as the pin engages the slot extension portions, and manually actuated means associated with the bit portions to cause them to move simultaneously outwardlyand inwardly.

5. In a screw driver, the combination of a shank having a narrow opening in the forward end thereof, and a longitudinal bore therethrough, a bit structure comprising a pair of undercut, complemental bit portions formed with substantially fiat surfaces engaging the sides of the narrow opening to prevent rotation therebetween, each bit portion including a rearwardly extending plate havinga cam surface comprising a longitudinal slot, and a slot extension lying at an angle to the longitudinal slot, the plates of the bit portions overlying one another, a pin fixed to said shank and passing through such slots, whereby outward movement of the bit portions causes such portions to diverge as the cam surfaces act against the pin, and inward movement of the portions causes the same to converge, and means for moving such bit portions simultaneously, inwardly and outwardly.

6. In a screw driver, the combination of a shank having a substantially rectangular opening in the forward end thereof, and a longitudinal bore therethrough, a bit structure comprising a pair of undercut, complemental bit portions formed with substantially flat surfaces engaging the sides of the narrow opening to prevent r0- tation therebetween, each bit portion including a rearwardly extending plate having a longitudinal slot and a slot extension lying at an angle to the longitudinal slot and forming opposed cam surfaces, the plates of the bit portions overlying one another, a fixed pin passing through such slots, whereby outward movement of the bit portions causes such portions to diverge as the cam surfaces act against the pin, and inward movement of theportions causes the same to converge, and means for moving such bit portions simultaneously, comprising a manually movable control rod mounted within the shank and secured to one of the bit portions, an-d complemental shoulders formed on the bit portions.

THEODOR A. OLEARY. 

